Discovery signal block mapping

ABSTRACT

Systems, methods, apparatuses, and computer program products for signal block mapping are provided. One method includes configuring, by a network node (e.g., base station or eNB), a group of discovery signaling blocks. The method may then include mapping the discovery signaling blocks of the group onto a subframe structure, including the group information into each of the discovery signaling blocks, and transmitting the discovery signaling blocks in the subframe structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/705,905, filed Dec. 6, 2019, which is a continuation of U.S.application Ser. No. 14/993,296 filed on Jan. 12, 2016, now U.S. Pat.No. 10,536,940 issued on Jan. 14, 2020. The contents of these earlierfiled applications are hereby incorporated by reference in theirentirety.

BACKGROUND Field

Embodiments of the invention generally relate to wireless or mobilecommunications networks, such as, but not limited to, the UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access Network(UTRAN), Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), LTE-Advanced(LTE-A), 5^(th) generation (5G) radio access technology, and/or HighSpeed Packet Access (HSPA). In particular, some embodiments may relateto frame structures for 5G cellular systems.

Description of the Related Art

Universal Mobile Telecommunications System (UMTS) Terrestrial RadioAccess Network (UTRAN) refers to a communications network including basestations, or Node Bs, and for example radio network controllers (RNC).UTRAN allows for connectivity between the user equipment (UE) and thecore network. The RNC provides control functionalities for one or moreNode Bs. The RNC and its corresponding Node Bs are called the RadioNetwork Subsystem (RNS). In case of E-UTRAN (enhanced UTRAN), no RNCexists and radio access functionality is provided in the evolved Node B(eNodeB or eNB) or many eNBs. Multiple eNBs may be involved for a singleUE connection, for example, in case of Coordinated MultipointTransmission (CoMP) and in dual connectivity.

Long Term Evolution (LTE) or E-UTRAN provides a new radio accesstechnology and refers to the improvements of UMTS through improvedefficiency and services, lower costs, and use of new spectrumopportunities. In particular, LTE is a 3GPP standard that provides foruplink peak rates of at least, for example, 75 megabits per second(Mbps) per carrier and downlink peak rates of at least, for example, 300Mbps per carrier. LTE supports scalable carrier bandwidths from 20 MHzdown to 1.4 MHz and supports both Frequency Division Duplexing (FDD) andTime Division Duplexing (TDD).

As mentioned above, LTE may also improve spectral efficiency innetworks, allowing carriers to provide more data and voice services overa given bandwidth. Therefore, LTE is designed to fulfill the needs forhigh-speed data and media transport in addition to high-capacity voicesupport. Advantages of LTE include, for example, high throughput, lowlatency, FDD and TDD support in the same platform, an improved end-userexperience, and a simple architecture resulting in low operating costs.

Certain releases of 3GPP LTE (e.g., LTE Rel-10, LTE Rel-11, LTE Rel-12,LTE Rel-13) are targeted towards international mobile telecommunicationsadvanced (IMT-A) systems, referred to herein for convenience simply asLTE-Advanced (LTE-A).

LTE-A is directed toward extending and optimizing the 3GPP LTE radioaccess technologies. A goal of LTE-A is to provide significantlyenhanced services by means of higher data rates and lower latency withreduced cost. LTE-A is a more optimized radio system fulfilling theinternational telecommunication union-radio (ITU-R) requirements forIMT-Advanced while keeping the backward compatibility.

In LTE (or LTE-A), there may be two downlink synchronization signalswhich are used by a UE to obtain cell identity and frame timing Thesesynchronization signals are referred to as the primary synchronizationsignal (PSS) and the secondary synchronization signal (SSS). Thedivision of the synchronization signals into two signals is aimed atreducing the complexity of the cell search process.

5G (5th generation mobile networks) refers to the new generation ofradio systems and network architecture delivering extreme broadband andultra-robust, low latency network connectivity. 5G networks are expectedto support data rates of several tens of megabits per second for tens ofthousands of users, to support several hundreds of thousands ofsimultaneous connections for massive sensor deployments, tosignificantly enhance spectral efficiency compared to LTE, to improvecoverage, to enhance signaling efficiency, and to significantly reducelatency compared to LTE.

SUMMARY

One embodiment includes a method, which may include configuring, by anetwork node, a group of discovery signaling blocks. The method may alsoinclude mapping the discovery signaling blocks of the group onto asubframe structure, including the group information into each of thediscovery signaling blocks, and transmitting the discovery signalingblocks in the subframe structure.

Another embodiment is directed to an apparatus, which includes at leastone processor and at least one memory comprising computer program code.The at least one memory and the computer program code are configured,with the at least one processor, to cause the apparatus at least toconfigure a group of discovery signaling blocks, map the discoverysignaling blocks of the group onto a subframe structure, include thegroup information into each of the discovery signaling blocks, andtransmit the discovery signaling blocks in the subframe structure.

Another embodiment is directed to an apparatus including configuringmeans for configuring a group of discovery signaling blocks, mappingmeans for mapping the discovery signaling blocks of the group onto asubframe structure, including means for including the group informationinto each of the discovery signaling blocks, and transmitting means fortransmitting the discovery signaling blocks in the subframe structure.

Another embodiment is directed to a computer program embodied onnon-transitory computer readable medium. The computer program isconfigured to control a processor to perform a process comprisingconfiguring a group of discovery signaling blocks, mapping the discoverysignaling blocks of the group onto a subframe structure, including thegroup information into each of the discovery signaling blocks, andtransmitting the discovery signaling blocks in the subframe structure.

Another embodiment is directed to a method, which may include detecting,by a user equipment, one or more discovery signaling blocks. The methodmay also include determining a beam configuration applied for thedetected one or more blocks, determining a group structure of thedetected one or more discovery signaling blocks, determining a mappingof the detected one or more discovery signaling blocks on one or moresubframes, determining a structure of the one or more subframes based onthe determined group structure and determined mapping, and performinginitial access to a cell based on the determining steps.

Another embodiment is directed to an apparatus, which includes at leastone processor and at least one memory comprising computer program code.The at least one memory and the computer program code are configured,with the at least one processor, to cause the apparatus at least todetect one or more discovery signaling blocks, determine a beamconfiguration applied for the detected one or more blocks, determine agroup structure of the detected one or more discovery signaling blocks,determine a mapping of the detected one or more discovery signalingblocks on one or more subframes, determine a structure of the one ormore subframes based on the determined group structure and determinedmapping, and perform initial access to a cell based on the determiningsteps.

Another embodiment is directed to an apparatus including detecting meansfor detecting one or more discovery signaling blocks, determining meansfor determining a beam configuration applied for the detected one ormore blocks, determining means for determining the group structure ofthe detected one or more discovery signaling blocks, determining meansfor determining a mapping of the detected one or more discoverysignaling blocks on one or more subframes, determining means fordetermining a structure of the one or more subframes based on thedetermined group structure and determined mapping, and performing meansfor performing initial access to a cell based on the determining steps.

Another embodiment is directed to a computer program embodied onnon-transitory computer readable medium. The computer program isconfigured to control a processor to perform a process comprisingdetecting one or more discovery signaling blocks, determining a beamconfiguration applied for the detected one or more blocks, determining agroup structure of the detected one or more discovery signaling blocks,determining a mapping of the detected one or more discovery signalingblocks on one or more subframes, determining a structure of the one ormore subframes based on the determined group structure and determinedmapping, and performing initial access to a cell based on thedetermining steps.

BRIEF DESCRIPTION OF THE DRAWINGS

For proper understanding of the invention, reference should be made tothe accompanying drawings, wherein:

FIG. 1 illustrates an example of a general framework for radioarchitecture, according to an embodiment;

FIG. 2 illustrates an example of a sweeping operation, according to anembodiment;

FIG. 3 illustrates an example of DSB implementation options, accordingto an embodiment;

FIG. 4 illustrates further implementation options for DSB to enablenarrowband structure, according to an embodiment;

FIG. 5 illustrates configuration options for DSB groups, according toone embodiment;

FIG. 6 illustrates example mappings of DSBs into subframe structures,according to an embodiment;

FIG. 7a illustrates options for resource element use for theantenna/beam ports transmitting DSBs, according to an embodiment;

FIG. 7b illustrates example options for resource element use for theantenna/beam ports not transmitting DSBs on the subframes where DSBresources are defined, according to an embodiment;

FIG. 8a illustrates an example block diagram of an apparatus, accordingto an embodiment;

FIG. 8b illustrates an example block diagram of an apparatus, accordingto another embodiment;

FIG. 9a illustrates a flow diagram of a method, according to anembodiment;

FIG. 9b illustrates a flow diagram of a method, according to anotherembodiment;

FIG. 10a illustrates an example block diagram of an apparatus, accordingto another embodiment;

FIG. 10b illustrates an example block diagram of an apparatus, accordingto another embodiment;

FIG. 11 illustrates an example of DSB grouping being associated withsweeping, according to an embodiment;

FIG. 12a illustrates an example block diagram of DSB block allocation,according to one embodiment;

FIG. 12b illustrates an example block diagram of DSB block allocation,according to another embodiment; and

FIG. 12c illustrates an example block diagram of DSB block allocation,according to another embodiment.

DETAILED DESCRIPTION

It will be readily understood that the components of the invention, asgenerally described and illustrated in the figures herein, may bearranged and designed in a wide variety of different configurations.Thus, the following detailed description of embodiments of systems,methods, apparatuses, and computer program products for signal blockmapping, as represented in the attached figures, is not intended tolimit the scope of the invention, but is merely representative of someselected embodiments of the invention.

The features, structures, or characteristics of the invention describedthroughout this specification may be combined in any suitable manner inone or more embodiments. For example, the usage of the phrases “certainembodiments,” “some embodiments,” or other similar language, throughoutthis specification refers to the fact that a particular feature,structure, or characteristic described in connection with the embodimentmay be included in at least one embodiment of the present invention.Thus, appearances of the phrases “in certain embodiments,” “in someembodiments,” “in other embodiments,” or other similar language,throughout this specification do not necessarily all refer to the samegroup of embodiments, and the described features, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Additionally, if desired, the different functions discussed below may beperformed in a different order and/or concurrently with each other.Furthermore, if desired, one or more of the described functions may beoptional or may be combined. As such, the following description shouldbe considered as merely illustrative of the principles, teachings andembodiments of this invention, and not in limitation thereof.

Certain embodiments relate to frame structures for 5G cellular systems.5G systems are expected to utilize a wide variety of differenttransceiver architectures that may range from low digital degree hybridtransceiver architectures to full digital solutions.

3GPP Technical Report 37.842, titled “Radio Frequency (RF) requirementbackground for Active Antenna System (AAS) Base Station (BS) (Release12),” describes Base Station (BS) Radio Frequency (RF) requirements forActive Antenna System (AAS). The entire contents of the Technical Report(3GPP TR 37.842) is hereby incorporated by reference in its entirety.

FIG. 1 illustrates an example of a general framework for radioarchitecture. As illustrated in the example of FIG. 1, one transmitterunit (TXU) can be connected to {1 . . . L} antenna elements depending onthe transceiver unit (TXRU) virtualization, i.e., the mapping betweenTXRUs and Antenna Elements. The mapping may be either sub-array or fullconnection. In the sub-array model, one TXRU is connected to subset ofantenna elements where different subsets are disjoint; while in the fullconnection model, each TXRU is connected to each antenna element.

Radio distribution network (RDN) performs antenna virtualization in theradio frequency (RF) domain. Virtualization is not frequency selectivebut common to resource elements (REs) and signals. RDN may utilizeeither sub array or full connection mapping between TXRUs and AntennaElements.

In the transmitting direction, M antenna ports feed K TXRUs, and K TXRUsfeed L antenna elements where M≤K≤L. Complexity and power consumption ofbaseband processing and analog/digital (A/D) conversion likely limitsthe number of antenna ports M and TXRUs K to be much less than L in thecentimetre/millimetre wave (cmWave/mmWave) system where L can be fromtens up to hundreds (or even thousands). Power consumption of TXU(excluding PA) is mainly due to digital-to-analog converter (DAC) ofwhich power consumption is linearly proportional to bandwidth andexponentially proportional to the number of analog-to-digital converter(ADC) bits (P˜Bx2^(2R); where B is bandwidth and R is bits per sample).Typically, 16 bit ADCs are used, for example, in LTE. Thus, the powerconsumption of TXRU may limit the feasible number of TXRUs being less orsignificantly less than L. The number of TXRUs defines the number ofsignals that can be transmitted simultaneously per basic frequencyresource like a subcarrier in an OFDM based system.

The framework illustrated in FIG. 1 may be used to describe digitalbeamforming, hybrid beamforming, and analog beamforming systems. In adigital Active Antenna System (AAS), one or more spatial layers per UEare provided, digital precoding only is supported, K=L(M≤K), and thereis one-to-one mapping from TXRU to antenna element. In a hybrid ActiveAntenna System (AAS), one or more spatial layers per UE are provided,involves both analog and digital beamforming, K<L(M≤K), and there isone-to-many mapping from TXRU to antenna element. In an analog ActiveAntenna System (AAS), there is one spatial layer per UE, involves onlyanalog beamforming (no digital precoding), M=1, K<L, and there isone-to-many mapping from TXRU to antenna element.

The deployment scenario, carrier frequency and system bandwidth largelydetermine the selected transceiver architecture. Similarly, the mode ofoperation will see different options that will be used depending on theabove parameters. In certain scenarios, the cell may operate using asector wide antenna beam pattern, while in other scenarios the cell mayneed to operate using narrow beams to meet the required link budget. Asa complement to conventional cellular systems, operating with narrowbeams would apply also for common control signalling between basestations (BSs) and user equipment (UEs). Practically, that meanstransmitting downlink common signalling and receiving uplink commoncontrol signalling in a sweeping manner A target of the sweeping is tocover the whole sector by transmitting or receiving with one or multiplenarrow beams at a time that can cover only portion of the sector, asillustrated in the example of a sweeping operation depicted in FIG. 2.On the other hand, the cell may operate using sector beams or in case ofnarrow beams, the number of beams and time slots to transmit commoncontrol signaling may differ from one BS to another.

A general problem addressed by certain embodiments is how to providemeans to enable cell search and initial access in a way that the UEprocedures remain the same independent of the cell operation mode andtransceiver architecture at the BS. In other words, one objective is tobuild a common control signaling framework that can adapt to differenttransceiver architectures at the BS and number of beams and time slotsneeded for sweeping in case the BS operates in beam domain.

It may be assumed that certain discovery signaling block(s) allowing aUE to be able detect and measure the cell, as well as to be able toaccess to the cell will be defined. One block can be assumed to conveydownlink common control signaling which can be transmitted in sweepingmanner to the sector.

A more specific problem addressed by certain embodiments is how to mapthose discovery signaling blocks on the subframes in order to providecommon control signaling that scales across different transceiverarchitectures, different sweeping structures (total number of beams,number of parallel beams) and different operation scenarios (such ascell type, cell loading situation, number of active UEs, the need forenergy saving at UE/eNB, etc.).

Therefore, embodiments provide a scalable solution to map discoverysignaling blocks on the subframes to enable BS transceiver architectureand antenna system agnostic initial access procedures.

According to one embodiment, a discovery signal block (DSB), such ascommon control signaling, may be transmitted by the eNB according to apredefined amount of time and frequency resources common to all subframetypes (e.g., three time domain symbols are allocated for a given DSB ona certain bandwidth and the corresponding resource elements such assubcarriers). The DSB may be transmitted from the network by using thesame RF beams. Each DSB may be self-detectable and self-decodable.

In certain embodiments, DSBs may be grouped together. One group may haveone or multiple DSBs. Each DSB indicates its position within the groupand provides the group's parameters. Configuration of DSB structure (howmany DRBs in total and how many beams multiplexed per DSB) isconfigurable by the network. Configuration is not known a priori by UEsperforming initial search and access (purpose is to enable agnosticinitial search and access procedure for UE). Thus, each block may beself-detectable and self-decodable and provides UE information aboutbeam and DSB structure, operation mode (etc.), and other such essentialinformation and parameters to perform initial access. Grouping, as usedherein, refers to a set of DSB blocks of which transmissions can coverthe whole sector in spatial domain.

The grouping may, in one embodiment, be associated with sweeping, asillustrated in FIG. 11. There the number of DSBs is three, as anon-limiting example. For example, one DSB of the group is transmittedto one beam sector at a first time domain resource, which may be asubframe or a certain number (1, 2, 3, . . . N) of time domain symbols,a second DSB to a second sector, etc. In another embodiment, the eNB maytransmit all DSBs of the group for every narrow beam sector. Forexample, each DSB may be sent simultaneously by multiple beams, possiblyto different directions (up to BS implementation). Simultaneouslytransmitted beams may be next to each other in spatial domain orseparated (like a comb in spatial domain generated from parallel beams).Thus, one DSB covers a portion of the sector. Association of the beamsof the cell to DSBs is according to BS implementation. In oneembodiment, the eNB may signal the association in each DSB block so thatUE can learn the beam configuration of the cell. The UE detecting theone or more DSBs may then be able to identify beams of the block(s)(e.g. indices) among all the beams of the cell.

In one embodiment, location of DSBs within a DSB group in subframes(e.g., downlink (DL) only or Special-DL subframes) can be configured bythe BS. If the size of the group is one, the DSB may be located in DLcontrol symbols or shared among DL control and data symbols. This may bebecause likely such system is fully digital and operates with sectorbeams and can have frequency selective beamforming, while hybridarchitectures may utilize sweeping. If the size of the group is greaterthan one, DSBs may be located in the space reserved for DL data symbols(within a subframe). Each DSB may indicate the position of the DSBwithin the group and total number of DSBs within the group.

According to one embodiment, subframes allocated for DSB transmissionsmay be used in a different manner by different transceiver units(antenna ports/beam ports), and the BS may change the number oftransceiver units allocated for DSB transmission over time.

It is noted that, in certain embodiments, the DSB is mapped to a certainlocation in the subframe, and that certain antenna ports send the DSBperiodically in a sweeping manner. That may mean that the DSB istransmitted systematically over the whole cell with certain periodicityfrom these antenna ports/beams. However, for full digital architecture,the sweeping may not take place and sector beams, which can be digitallyprecoded, may be used instead. In addition, embodiments may providesimultaneous transmission of data and DSB in cases where the DSB coversonly some part of the bandwidth.

In a first embodiment, transceiver and antenna system agnostic accessmethods and systems are provided. In this embodiment, a discovery signalblock (DSB) is defined according to certain characteristics. Forexample, the DSB may have a predefined amount of time and frequencyresources common to all subframe types and deployed architectures. TheUE may assume that signals transmitted within a DSB are transmittedusing the same RF beams at the BS, i.e. the BS is not allowed to changebeamforming weights (digital and/or analog) within the DSB. For the UE,the property that it can assume signals transmitted using the same RFbeams means that UE can determine beam level timing synchronization(PSS/SSS to acquire timing and beam RS/CSI-RS to beam acquisition). Inco-operative multi-point (MP) scheme where multiple non-collocatedremote radio heads share the same cell ID it may be beneficial in somescenarios if one block comprises beams only from one remote radio head(RRH) at a time so that UE can derive beam specific timingsynchronization from synchronization signals, and radio head specifictiming synchronization. DSB may also include information about mappingof beams transmitting DSB to transmission points of remote radio headsboth in case RRH specific beams are in different DSBs or share the sameDSBs.

In an embodiment, the DSB may comprise multiple signals, for instance:synchronization signals for timing and partial or full physical layercell ID acquisition, data channel (e.g., physical broadcast channel),and/or antenna port/beam port specific reference signals for physicalbroadcast channel (PBCH) demodulation, beam detection, paging detectionand channel state information (CSI) acquisition.

Further, each DSB may be self-detectable and self-decodable. It is alsopossible to combine or average signals corresponding to different DSBtransmissions instants towards the same spatial direction.

DSBs may be grouped together (see FIG. 5 discussed below), and each DSBmay indicate its relationship within the group. A group of DSBs may havethe following properties: a group may have one (cell operates withsector wide beams) or multiple DSBs (cell operates with beams narrowerthan sector wide beams), a BS transmits a group of DSBs within a certainperiod where the period may be, for instance, periodicity UE can assumefor synchronization signal per spatial direction. DSBs within a groupcan be spread within a subframe or across multiple subframes.

FIG. 3 illustrates an example of DSB implementation options, accordingto an embodiment. As depicted in FIG. 3, a DSB may include a blockcapturing four signals: 2 synchronization signals, reference signal(beam reference signal/csi reference signal), and physical broadcastchannel It may also include signals and channels for paging support anddistributing system information on frequency resources not reserved bysynchronization signals and physical broadcast channel As for physicalbroadcast channel, beam reference signal would be used as demodulationreference signal for other channels in the block as well. Thesefrequency resources not reserved by synchronization signals and physicalbroadcast channel are depicted in FIG. 3 with the empty (white) blocks.The DSB in general can be seen to comprise also the shaded/marked blocksof FIG. 3. The size and content of the DSB block may vary per eNBimplementation and per detected transmission needs in the cell. DSB isconsidered to have a fixed amount of time and frequency domain resourcesindependent of the transceiver architecture and configuration of DSBs(in predetermined location within the carrier). In this example, threetime domain symbols may be allocated for DSB and a bandwidth ofBandwidth 2. Bandwidth 2 may be, for example, a system bandwidth.Bandwidth 1 is a reduced bandwidth for certain signals and channels inDSB. DSB may comprise, for example, synchronization signal(s) for timeand frequency synchronization, physical broadcast channel to conveysystem information, paging indicator and reference signal(s). Inaddition, there may be separate channels for most essential systeminformation, paging and other system information distribution. Theirperiodicity may differ from each other, i.e. in certain block there maybe only physical broadcast channel present while in some other blockthere may be physical broadcast channel, paging channel and channel forsystem information distribution present. All the signals and physicalchannels may be transmitted via multiple antenna ports in parallel.Antenna port/beam port specific reference signals may be allocatedorthogonal resources in frequency (frequency domain multiplexing(FDM)/Interleaved FDM) and/or code domains Reference signals may be usedfor demodulation reference signals for PBCH detection, mobilitymeasurements, beam detection, tracking and selection, CSI acquisition,etc. PBCH may be transmitted using transmit diversity method acrossparallel antenna/beam ports in order to use one set of resources perDSB. For cell search and physical broadcast channel detection, the UEmay operate only using reduced bandwidth option, Bandwidth 1.

FIG. 4 illustrates further implementation options for DSB to enablenarrowband structure, according to an embodiment. The example of FIG. 4may be used in case part of the transceiver resources (e.g., someantenna ports) are performing periodical DSB transmission while others(e.g., some of the other antenna ports) are transmitting dedicated UEsignalling on the DSB subframes.

FIG. 5 illustrates configuration options for DSB groups, according toone embodiment. As illustrated in FIG. 5, one group may have one ormultiple DSBs. Each DSB indicates its position within the group andprovides the group's parameters. DSBs within the group may be placedconsecutively in time domain or may be discontinuously allocated intime. An opportunity for RF beam switching is provided between DSBswithin a group. One OFDMA symbol may be reserved for such a guard timebetween DSB transmissions within a subframe. Other possibilities are todefine certain number of samples for the explicit guard period or reusefirst samples of the CP of the first symbol of the block for the guardperiod. Guard period used for link direction switching may also serve asa guard time between DSB transmissions (both within a subframe andbetween subframes).

In a second embodiment, configurability for DSB location withinsubframes is provided. Location of DSBs within a DSB group in subframes(e.g., DL only or S-DL subframes) may be configured by the BS. Theconfiguration may depend on the architecture used at the BS, as well asdepending on the operation mode, but the UE does not need any assumptionprior cell search. Thus, the configuration of the location of DSBs canbe performed in a UE agnostic manner.

According to an embodiment, the location of a DSB group may depend onthe size of the group. For example, if the size of the group is one, theDSB may be located in DL control symbols or shared among DL control anddata symbols. This is one possible configuration with digitalarchitecture operating using sector beams because it minimizes consumingresource elements from data symbols while downlink control flexibilitycan be maintained because of having frequency selective digitalbeamforming capability at the BS.

If the size of the group is greater than one, the DSBs may be located inthe space reserved for DL data symbols (within a subframe). Forinstance, DSB allocation may start from the end of the subframe (or fromthe end of DL data part of the subframe). This is a possibleconfiguration with hybrid/analog architecture operating using narrowbeams by not limiting flexibility for transmission of control symbols.It may be noted that demodulation reference signal (DMRS) may, in anembodiment, be located at the beginning of data part of the subframe (tofacilitate fast detection at the receiver). In case of low number ofDSBs that together fill only part of the subframe, filling from the endof the subframe may provide data transmission capability for datasymbols preceding DSB blocks. Assuming demodulation RS would precededata symbols, unused data symbols due to DSB blocks would be more faraway from DMRS than used ones. Furthermore, possibilities for havingDMRS available in the “shorted subframe” can be maximized with thisapproach.

In an embodiment, the following rules may be defined for allocatingDSB(s) of the DSB group into subframes. Each DSB may indicate theposition of the DSB within the group and the total number of DSBs withinthe group. The maximum number of time domain DSB resources may bedefined for subframe (e.g., 6). The maximum number may be needed inorder for the UE to derive resource elements which are used by the DSBgroup in case DSBs within a group are spread across multiple subframes.In one example, the number can be fixed and defined in the specificationfor the subframe per subframe type (maximum number may depend onsubframe type as well). In another example, the number can be defined bythe BS/network system. In that case, each DSB would include informationto the UE. This information (related to target cell) may also beincluded in a handover command to the UE. Another approach could be touse, for example, another RAT in case of multi-radio connectivityapplied (UE could be connected to LTE when searching 5G cells and LTEprovides information). According to one embodiment, if the number ofDSBs within the group is greater than the maximum number of time domainDSB resources for the subframe, DSBs may be spread across consecutivesubframes having downlink data symbols (e.g., consecutive DL onlysubframes). If the DSB group has only one DSB, it may be allocated intothe downlink control symbols, partly over downlink control and partlyover downlink data symbols, or anywhere in the subframe. In the case itis allocated anywhere in the subframe, the DSB includes information forthe UE to derive its location (i.e., mapping information) in relation tocurrent subframe structure. This may be needed as there may be a need todefine DSB resources and subframe structure (including DL controlresource dimensioning in the subframe) independently from each other. Insome embodiments, the mapping information is implicit (such as DSB isalways mapped to the last symbol(s) of the subframe), whereas in othercases the DSB includes an explicit indication of the mappinginformation. On the other hand, DSB may indicate (OFDM) symbol timingwithin the subframe. Hence, DSB may include indication about thosesymbol number(s) on the subframe on which the detected DSB block isallocated upon.

In one embodiment the UE may detect the subframe structure from thereceived DSB. One example is that DSB indicates for instance maximumnumber (max_num) of DBSs within subframe which may indicate indirectlyhow many symbols are actually allocated for downlink control in thesubframe. For example, if max_num of DSBs within subframe is three, thatcould mean two control symbols, but if the max_num of DSBs withinsubframe is four that could mean only one downlink control symbol only.Further, certain value may indicate that there is no uplink controlsymbol in the subframe where at least one DSB is allocated.

Furthermore, if the number of DSBs within the group is greater thandefined maximum number for allowed consecutive blocks, DSBs of the groupmay be allocated into clusters within the period. For example, if themaximum number for allowed consecutive blocks is 6 and there are 9blocks in the group, 6 blocks are allocated consecutively in time andrest 3 blocks are allocated consecutively in time with some offset fromthe cluster of blocks defined by said first 6 blocks. For instance, thecluster of blocks defined by said second 3 blocks are allocated on thesubframe(s) with time offset half of the period of the group to the saidfirst cluster. Another example is to increase the periodicity of theDSBs by the number of created clusters of blocks. For example, if thebasic periodicity is 6 ms, the BS has configured 24 blocks and themaximum number for allowed blocks is 8, three clusters of DSBs arecreated within the group. The clusters are separated by 2 ms from eachother or alternatively, basic periodicity for each DSB is increased byfactor of three to 18 ms and clusters are separated by 6 ms. In anotheralternative, maximum allowed consecutive blocks is configured toinfinite and using above assumptions, all 24 blocks are allocatedconsecutively in time domain (potentially omitting downlink and/oruplink control symbols) and spread across multiple consecutivesubframes.

FIG. 6 illustrates example mappings of DSBs into subframe structures,according to an embodiment. In the example of FIG. 6, DSBs are depictedas narrowband blocks relative to the total system bandwidth.Alternatively, as discussed above, DSB block may have some signals thatare allocated total system bandwidth. As one implementation option, beamRS bandwidth could be configurable and could be signaled via DSB. Bydefault UE could always assume certain minimum bandwidth for beam RS inorder to enable demodulation of PBCH using beam RS, initial measurementsand beam selection when performing initial search and access to thecell. DSB may then indicate whether or not the beam RS is allocated overthe full bandwidth or over narrow bandwidth.

In a third embodiment, adaptability of multiplexing of DSBs is provided.In this embodiment, subframes allocated for DSB transmissions may beused in different manner by different transceiver units (antennaports/beam ports). For example, certain transceiver resources maytransmit DSBs and certain transceiver resources may be used(simultaneously) for dedicated UE signaling (control and data) in thosesubframes. In this case, it may be desirable to define DSB to be narrowbandwidth block used by dedicated transceiver units while the rest ofthe system bandwidth could be used for dedicated signaling by othertransceiver units (in other words to apply FDM between user data andDSB). For instance, one or two transceiver units may be allocated forsweeping DSBs while other transceiver units may be allocated for servingonly dedicated UE signaling (control and data). In subframes DSBs arenot transmitted, all transceiver units may be allocated for dedicated UEsignaling.

The BS may change number of transceiver units allocated for DSBtransmission over time. For example, when the cell is empty, the BS mayminimize the sweeping time by multiplexing all beam ports into one DSBtransmission; while, when the cell is serving a high number of UEs, DSBtransmissions may be performed by, for example, one or two antenna/beamports. Here it is assumed that a single beam provides enough EIRP forcommon control signaling from link budget/coverage point of view andthus multiple beams can be transmitted in parallel to different spatialdirections. In case of narrowband DSB, a possibility is to allocate someantenna ports to transmit DSBs in parallel and other antenna ports totransmit user plane data at the same time on the frequency resources notreserved by DSBs. When the cell is empty, energy consumption isdetermined by the time the BS needs to have its transmitter(s) on. Thus,assuming certain total number of beams for full sweep, the sweep can bemade shorter in time if more beams can be transmitted in parallel.Narrowband DSB would allow such configurability, for example when cellis empty the BS uses all the antenna ports in parallel for sweep, whenthere is load in the cell (high load), some APs perform sweeping whileother perform user plane data transmission, thus preventing creation ofdata transmission gaps in downlink user plane transmissions due tosweeping.

As the DSB indicates the number of multiplexed beam ports per DSB andthe total number of beam ports, the UE can derive the configuration ofthe transceiver units for DSB transmission to be able to track BS beams.

FIG. 7a illustrates options for resource element use for theantenna/beam ports transmitting DSBs, according to an embodiment. FIG.7b depicts options for resource element use for the antenna/beam portsnot transmitting DSBs on the subframes where DSB resources are defined,according to an embodiment. If PDSCH data allocation covers DSB region,the corresponding (dedicated) data/RS can be either rate matched orpunctured around resource elements covering DSB region.

In case of narrowband DSB definition, one alternative may be to allocateDSB resource elements onto the edge of the system bandwidth to enablecontinuous allocation in frequency domain possibility for the antennaports not transmitting DSBs on the subframes having DSB allocations.That would be beneficial, for instance, with single carrier transmissionmodulation schemes because DSBs are not in the middle of the systembandwidth to break frequency domain into two clusters.

FIG. 8a illustrates an example of an apparatus 10 according to anembodiment. In an embodiment, apparatus 10 may be a node, host, orserver in a communications network or serving such a network. Forexample, in certain embodiments, apparatus 10 may be a network node oraccess node for a radio access network, such as a base station e.g.,NodeB (NB) in UMTS or eNodeB (eNB) in LTE or LTE-A. However, in otherembodiments, apparatus 10 may be other components within a radio accessnetwork. It should be noted that one of ordinary skill in the art wouldunderstand that apparatus 10 may include components or features notshown in FIG. 8 a.

As illustrated in FIG. 8a , apparatus 10 includes a processor 22 forprocessing information and executing instructions or operations.Processor 22 may be any type of general or specific purpose processor.While a single processor 22 is shown in FIG. 8a , multiple processorsmay be utilized according to other embodiments. In fact, processor 22may include one or more of general-purpose computers, special purposecomputers, microprocessors, digital signal processors (DSPs),field-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and processors based on a multi-core processorarchitecture, as examples.

Apparatus 10 may further include or be coupled to a memory 14 (internalor external), which may be coupled to processor 22, for storinginformation and instructions that may be executed by processor 22.Memory 14 may be one or more memories and of any type suitable to thelocal application environment, and may be implemented using any suitablevolatile or nonvolatile data storage technology such as asemiconductor-based memory device, a magnetic memory device and system,an optical memory device and system, fixed memory, and removable memory.For example, memory 14 can be comprised of any combination of randomaccess memory (RAM), read only memory (ROM), static storage such as amagnetic or optical disk, or any other type of non-transitory machine orcomputer readable media. The instructions stored in memory 14 mayinclude program instructions or computer program code that, whenexecuted by processor 22, enable the apparatus 10 to perform tasks asdescribed herein.

In some embodiments, apparatus 10 may also include or be coupled to oneor more antennas 25 for transmitting and receiving signals and/or datato and from apparatus 10. Apparatus 10 may further include or be coupledto a transceiver 28 configured to transmit and receive information. Forinstance, transceiver 28 may be configured to modulate information on toa carrier waveform for transmission by the antenna(s) 25 and demodulateinformation received via the antenna(s) 25 for further processing byother elements of apparatus 10. In other embodiments, transceiver 28 maybe capable of transmitting and receiving signals or data directly.

Processor 22 may perform functions associated with the operation ofapparatus 10 which may include, for example, precoding of antennagain/phase parameters, encoding and decoding of individual bits forminga communication message, formatting of information, and overall controlof the apparatus 10, including processes related to management ofcommunication resources.

In an embodiment, memory 14 may store software modules that providefunctionality when executed by processor 22. The modules may include,for example, an operating system that provides operating systemfunctionality for apparatus 10. The memory may also store one or morefunctional modules, such as an application or program, to provideadditional functionality for apparatus 10. The components of apparatus10 may be implemented in hardware, or as any suitable combination ofhardware and software.

In one embodiment, apparatus 10 may be a network node or access node,such as a base station in UMTS or an eNB in LTE or LTE-A, for example.According to certain embodiments, apparatus 10 may be controlled by atleast one memory 14 and at least one processor 22 to configure a groupof discovery signaling blocks (DSBs). Apparatus 10 may configure a DSBaccording to certain characteristics. For example, the DSB may have apredefined amount of time and frequency resources common to all subframetypes and deployed architectures.

As mentioned above, in an embodiment, the DSB may comprise multiplesignals, for instance: synchronization signals for timing and partial orfull physical layer cell ID acquisition, data channel (e.g. physicalbroadcast channel), and/or antenna port/beam port specific referencesignals for physical broadcast channel (PBCH) demodulation, pagingdetection, beam detection, and channel state information (CSI)acquisition. FIGS. 3 and 4 discussed in detail above illustrate examplesof a DSB configuration.

In addition, DSBs may be grouped together as illustrated in FIG. 5discussed above, and each DSB may indicate its relationship within thegroup. The group may include one or multiple DSBs. In an embodiment,apparatus 10 may configure the location of DSBs within a DSB group insubframes (e.g., DL only or S-DL subframes). According to oneembodiment, DSBs of the group may be located consecutively in time or ina clustered manner in time. One DSB may include transmission of aplurality of signals from one or multiple radio frequency beams, and theone or more radio frequency beams used for the transmission of thesignals in a given DSB are the same.

In an embodiment, apparatus 10 may be further controlled by at least onememory 14 and at least one processor 22 to map the DSBs of the grouponto a subframe structure, and to include the group information into theDSBs. According to one embodiment, mapping information may also beincluded into the DSBs. In an embodiment, when mapping DSB(s) of the DSBgroup into subframes, each DSB may indicate the position of the DSBwithin the group (i.e., mapping information) and the total number ofDSBs within the group (i.e., group information). According to oneexample, the maximum number of time domain DSB resources may be definedfor a subframe. In one embodiment, the maximum number may be fixed anddefined in the specification for the subframe. In another embodiment,the maximum number may be defined by apparatus 10. In one embodiment,apparatus 10 may be further controlled by at least one memory 14 and atleast one processor 22 to transmit the DSBs in the subframe structure.

According to one embodiment, apparatus 10 may be controlled by at leastone memory 14 and at least one processor 22 to map the DSBs onto thesubframe structure based on a size of the group and/or based on thesubframe structure type configured in the cell. In an embodiment, theDSBs are not allocated upon downlink and/or uplink control channelsymbols if a number of subframes upon which blocks are mapped in aconsecutive manner is below a given value.

When the number of consecutive subframes that the DSBs are allocatedupon is greater than a given value, there may be another valueindicating on how many subframes control symbols are remaining. FIGS.12a, 12b, and 12c illustrate examples of DSBs allocation. For example,the first value could be 4 and the second value is 2, as non-limitingexamples and other values are possible. These values may be pre-storedin the transmitting and receiving entities. In case the number ofconsecutive subframes is greater than four (=first value), e.g. six,then downlink control symbols are remained on the two (according tosecond value) edge subframes of the subframes DSBs are allocated uponand control symbols are omitted from other subframes. Alternatively,there may be some pattern on which subframes control symbols areremained in case the number of consecutive subframes DSBs are allocatedis greater than given value (first value). The values may refer to anumber of subframes. Downlink and uplink control symbols may be needed,for instance, for transmitting and receiving HARQ ack/nack feedback onprevious subframes (data subframes) and sending scheduling grants forcoming subframes.

Returning to FIG. 8a , in an embodiment, apparatus 10 may be controlledby at least one memory 14 and at least one processor 22 to map the DSBsin a subframe starting from the end of the data symbols, when the groupsize is greater than one. For example, the blocks of the group may bemapped upon last downlink symbols of the subframe. In anotherembodiment, apparatus 10 may be controlled by at least one memory 14 andat least one processor 22 to map the DSBs in a subframe starting from adownlink control symbol and/or downlink data symbol when the group sizeis one. Applying only one DSB block may mean that the BS can cover thewhole sector at once. In one embodiment, in hybrid/analog beamforming,even if there is only one DSB block in the group, that one DSB may besituated at the end of the subframe (one or more of the last symbols ofthe subframe).

In one embodiment, the number of radio frequency beams per block may beconfigured by apparatus 10. According to one embodiment, at least oneradio frequency beam is transmitting block and at least one other radiofrequency block is transmitting data symbols simultaneously. Radioresources for DSBs and data symbols may be separated in frequencydomain.

FIG. 8b illustrates an example of an apparatus 20 according to anotherembodiment. In an embodiment, apparatus 20 may be a node or element in acommunications network or associated with such a network, such as a UE,mobile device, mobile unit, machine type UE or other device. Forinstance, in some embodiments, apparatus 20 may be UE in LTE or LTE-A.It should be noted that one of ordinary skill in the art wouldunderstand that apparatus 20 may include components or features notshown in FIG. 8 b.

As illustrated in FIG. 8b , apparatus 20 includes a processor 32 forprocessing information and executing instructions or operations.Processor 32 may be any type of general or specific purpose processor.While a single processor 32 is shown in FIG. 8b , multiple processorsmay be utilized according to other embodiments. In fact, processor 32may include one or more of general-purpose computers, special purposecomputers, microprocessors, digital signal processors (DSPs),field-programmable gate arrays (FPGAs), application-specific integratedcircuits (ASICs), and processors based on a multi-core processorarchitecture, as examples.

Apparatus 20 may further include or be coupled to a memory 34 (internalor external), which may be coupled to processor 32, for storinginformation and instructions that may be executed by processor 32.Memory 34 may be one or more memories and of any type suitable to thelocal application environment, and may be implemented using any suitablevolatile or nonvolatile data storage technology such as asemiconductor-based memory device, a magnetic memory device and system,an optical memory device and system, fixed memory, and removable memory.For example, memory 34 can be comprised of any combination of randomaccess memory (RAM), read only memory (ROM), static storage such as amagnetic or optical disk, or any other type of non-transitory machine orcomputer readable media. The instructions stored in memory 34 mayinclude program instructions or computer program code that, whenexecuted by processor 32, enable the apparatus 20 to perform tasks asdescribed herein.

In some embodiments, apparatus 20 may also include or be coupled to oneor more antennas 35 for transmitting and receiving signals and/or datato and from apparatus 20. Apparatus 20 may further include a transceiver38 configured to transmit and receive information. For instance,transceiver 38 may be configured to modulate information on to a carrierwaveform for transmission by the antenna(s) 35 and demodulateinformation received via the antenna(s) 35 for further processing byother elements of apparatus 20. In other embodiments, transceiver 38 maybe capable of transmitting and receiving signals or data directly.

Processor 32 may perform functions associated with the operation ofapparatus 20 including, without limitation, precoding of antennagain/phase parameters, encoding and decoding of individual bits forminga communication message, formatting of information, and overall controlof the apparatus 20, including processes related to management ofcommunication resources.

In an embodiment, memory 34 stores software modules that providefunctionality when executed by processor 32. The modules may include,for example, an operating system that provides operating systemfunctionality for apparatus 20. The memory may also store one or morefunctional modules, such as an application or program, to provideadditional functionality for apparatus 20. The components of apparatus20 may be implemented in hardware, or as any suitable combination ofhardware and software.

As mentioned above, according to one embodiment, apparatus 20 may be amobile device, such as a UE in LTE or LTE-A. In one embodiment,apparatus 20 may be controlled by at least one memory 34 and at leastone processor 32 to detect one or more DSBs, determine a beamconfiguration applied for the detected one or more DSBs, determine thegroup structure of the detected one or more DSBs, and determine amapping of the detected one or more DSBs on one or more subframes.Apparatus 20 may also be controlled by at least one memory 3 and atleast one processor 32 to determine a structure of the one or moresubframes based on the determined group structure and the determinedmapping, and to perform initial access to a cell of the network based onthe result of the determining steps.

FIG. 9a illustrates an example flow diagram of a method, according toone embodiment of the invention. In certain embodiments, the method ofFIG. 9a may be performed by a network node, such as a base station oreNB. As illustrated in FIG. 9a , the method may include, at 900,configuring a group of discovery signaling blocks (DSBs). The group ofDSBs may be configured according to certain characteristics. Forexample, the DSB may have a predefined amount of time and frequencyresources common to all subframe types and deployed architectures.

As mentioned above, in an embodiment, the DSB may comprise multiplesignals, such as synchronization signals for timing and partial or fullphysical layer cell ID acquisition, data channel (e.g. physicalbroadcast channel), and/or antenna port/beam port specific referencesignals for physical broadcast channel (PBCH) demodulation, pagingdetection, beam detection, and channel state information (CSI)acquisition.

In addition, DSBs may be grouped together as illustrated in FIG. 5discussed above, and each DSB may indicate its relationship within thegroup. The group may include one or multiple DSBs. In an embodiment, theconfiguring may include configuring the location of DSBs within a DSBgroup in subframes (e.g., DL only or S-DL subframes). According to oneembodiment, DSBs of the group may be located consecutively in time or ina clustered manner in time. One block may include transmission from oneor multiple radio frequency beams.

In an embodiment, the method may further include, at 910, mapping theDSBs of the group onto a subframe structure, and, at 920, including thegroup information into each of the DSB(s). According to one embodiment,the including may further comprise including the mapping information inthe DSBs. In an embodiment, when mapping DSB(s) of the DSB group intosubframes, each DSB may indicate the position of the DSB within thegroup and the total number of DSBs within the group. According to oneexample, the maximum number of time domain DSB resources may be definedfor a subframe. In one embodiment, the maximum number may be fixed anddefined in the specification for the subframe. In another embodiment,the maximum number may be defined by the base station or eNB. The methodmay further include, at 925, transmitting the DSB(s) in the subframestructure.

According to one embodiment, the mapping may include mapping the DSBsonto the subframe structure based on a size of the group and/or based onthe subframe structure type configured in the cell. In an embodiment,the DSBs are not allocated upon downlink and/or uplink control channelsymbols if a number of subframes upon which blocks are mapped in aconsecutive manner is below a given value. In an embodiment, the mappingmay include mapping the DSBs in a subframe starting from the end of thedata symbols, when the group size is greater than one. In anotherembodiment, the mapping may include mapping the DSBs in a subframestarting from a downlink control symbol and/or downlink data symbol whenthe group size is one.

In one embodiment, the number of radio frequency beams per block may beconfigured by the base station or eNB. According to one embodiment, atleast one radio frequency beam is transmitting block and at least oneother radio frequency block is transmitting data symbols simultaneously.Radio resources for DSBs and data symbols may be separated in frequencydomain.

FIG. 9b illustrates an example flow diagram of a method, according toanother embodiment of the invention. In certain embodiments, the methodof FIG. 9b may be performed by a device, such as a UE in LTE or LTE-A.As illustrated in FIG. 9b , the method may include, at 950, detectingone or more DSBs. At 960, the method may include determining a beamconfiguration applied for the detected one or more DSBs. The method mayfurther include, at 970, determining the group structure of the detectedone or more DSBs, and, at 980, determining a mapping of the detected oneor more DSBs on one or more subframes. The method may also include, at985, determining a structure of the one or more subframes based on thedetermined group structure and the determined mapping. The method maythen include, at 990, performing initial access to a cell of the networkbased on the result of the determining steps.

FIG. 10a illustrates a block diagram of an apparatus 800, according toone embodiment. As illustrated in the example of FIG. 10a , apparatus800 may include a processing unit or means 801 for controlling apparatus800 and for carrying out instructions of a computer program, forexample, by performing arithmetic, logical, control and input/output(I/O) operations specified by the instructions. Apparatus 800 may alsoinclude a storage unit or means 803 for storing information including,but not limited to, computer program instructions or software modulesthat provide functionality when executed by processing unit 801.Apparatus 800 may further include a transceiving unit or means 802 forreceiving or transmitting information. Apparatus 800 may also include aconfiguring unit or means 804 and a mapping unit or means 805. In anembodiment, the configuring unit 804 may configure a group of discoverysignaling blocks (DSBs). The group of DSBs may be configured accordingto certain characteristics. For example, the DSB may have a predefinedamount of time and frequency resources common to all subframe types anddeployed architectures.

The group may include one or multiple DSBs. In an embodiment, theconfiguring unit 804 may configure the location of DSBs within a DSBgroup in subframes (e.g., DL only or S-DL subframes). According to oneembodiment, DSBs of the group may be located consecutively in time or ina clustered manner in time. One block may include transmission from oneor multiple radio frequency beams.

In an embodiment, mapping unit 805 may map the DSBs of the group onto asubframe structure. The configuring unit 804 may cause the including ofthe group information and optionally the mapping information into theDSBs. In an embodiment, when mapping DSB(s) of the DSB group intosubframes, each DSB may indicate the position of the DSB within thegroup and the total number of DSBs within the group. According to oneexample, the maximum number of time domain DSB resources may be definedfor a subframe. In one embodiment, the maximum number may be fixed anddefined in the specification for the subframe. In another embodiment,the maximum number may be defined by apparatus 800. Transceiving unit ormeans 802 may cause the transmitting of the DSBs in the subframestructure.

According to one embodiment, the mapping unit 805 may map the DSBs ontothe subframe structure based on a size of the group and/or based on thesubframe structure type configured in the cell. In an embodiment, theDSBs are not allocated upon downlink and/or uplink control channelsymbols if a number of subframes upon which blocks are mapped in aconsecutive manner is below a given value. In an embodiment, the mappingunit 805 may map the DSBs in a subframe starting from the end of thedata symbols, when the group size is greater than one. In anotherembodiment, the mapping unit 805 may map the DSBs in a subframe startingfrom a downlink control symbol and/or downlink data symbol when thegroup size is one.

In one embodiment, the number of radio frequency beams per block may beconfigured by the base station or eNB. According to one embodiment, atleast one radio frequency beam is transmitting block and at least oneother radio frequency block is transmitting data symbols simultaneously.Radio resources for DSBs and data symbols may be separated in frequencydomain.

FIG. 10b illustrates a block diagram of an apparatus 850, according toone embodiment. As illustrated in the example of FIG. 10b , apparatus850 may include a processing unit or means 851 for controlling apparatus850 and for carrying out instructions of a computer program, forexample, by performing arithmetic, logical, control and input/output(I/O) operations specified by the instructions. Apparatus 850 may alsoinclude a storage unit or means 853 for storing information including,but not limited to, computer program instructions or software modulesthat provide functionality when executed by processing unit 851.Apparatus 850 may further include a transceiving unit or means 852 forreceiving or transmitting information. Apparatus 850 may also include adetecting unit 854 and a determining unit 855.

In an embodiment, detecting unit 854 may detect one or more DSBs.Determining unit 855 may determine a beam configuration applied for thedetected one or more blocks, determine the group structure of thedetected one or more DSBs, determine a mapping of the detected one ormore DSBs on one or more subframes, and determine a structure of the oneor more subframes based on the determined group structure and thedetermined mapping. The transceiving unit or means 852 may cause theperforming of initial access to a cell of the network based on theresult of the determining steps.

Embodiments of the invention provide several advantages and technicalimprovements. For example, embodiments support all possible BSarchitectures (fully digital, hybrid, fully analog). In addition,embodiments are UE agnostic. In other words, the UE does not need toknow the BS architecture in advance. Further, embodiments may supportboth beamformed and conventional (sector beam approach) approaches forthe common control plane (PBCH, PRACH). Certain embodiments havebuilt-in support for efficient usage of BS TXRU (and other hardwareresources). Also, embodiments allow for minimizing the duration of onesweep of beamformed control channel transmission. Hence, it has apositive impact on the UEs power consumption (i.e., UE power consumptionis reduced). Additionally, embodiments allow simultaneous transmissionof data and DSB. This will minimize the system overhead of DSBtransmission.

According to embodiments, programs, also called program products orcomputer programs, including software routines, applets and macros, maybe stored in any apparatus-readable data storage medium and they includeprogram instructions to perform particular tasks. A computer programproduct may comprise one or more computer-executable components which,when the program is run, are configured to carry out embodiments. Theone or more computer-executable components may be at least one softwarecode or portions of it. Modifications and configurations required forimplementing functionality of an embodiment may be performed asroutine(s), which may be implemented as added or updated softwareroutine(s). Software routine(s) may be downloaded into the apparatus.

Software or a computer program code or portions of it may be in a sourcecode form, object code form, or in some intermediate form, and it may bestored in some sort of carrier, distribution medium, or computerreadable medium, which may be any entity or device capable of carryingthe program. Such carriers include a record medium, computer memory,read-only memory, photoelectrical and/or electrical carrier signal,telecommunications signal, and software distribution package, forexample. Depending on the processing power needed, the computer programmay be executed in a single electronic digital computer or it may bedistributed amongst a number of computers. The computer readable mediumor computer readable storage medium may be a non-transitory medium.

In other embodiments, the functionality of any method or apparatusdescribed herein may be performed by hardware, for example through theuse of an application specific integrated circuit (ASIC), a programmablegate array (PGA), a field programmable gate array (FPGA), or any othercombination of hardware and software. In yet another embodiment, thefunctionality may be implemented as a signal, a non-tangible means thatmay be carried by an electromagnetic signal downloaded from the Internetor other network.

According to an embodiment, an apparatus, such as a node, device, or acorresponding component, may be configured as a computer or amicroprocessor, such as single-chip computer element, or as a chipset,including at least a memory for providing storage capacity used forarithmetic operation and an operation processor for executing thearithmetic operation.

One having ordinary skill in the art will readily understand that theinvention as discussed above may be practiced with steps in a differentorder, and/or with hardware elements in configurations which aredifferent than those which are disclosed. Therefore, although theinvention has been described based upon these preferred embodiments, itwould be apparent to those of skill in the art that certainmodifications, variations, and alternative constructions would beapparent, while remaining within the spirit and scope of the invention.In order to determine the metes and bounds of the invention, therefore,reference should be made to the appended claims.

We claim:
 1. An apparatus, comprising: at least one processor; and atleast one memory comprising computer program code, the at least onememory and the computer program code are configured, with the at leastone processor, to cause the apparatus at least to detect in a subframestructure one or more discovery signaling blocks associated withindices, wherein a discovery signaling block comprises at least asynchronization signal and a physical broadcast channel; based on theassociated indices of the one or more detected discovery signalingblocks, determine a group structure of the discovery signaling blocks;based on the group structure of the discovery signaling blocks,determine a beam among the beams of the cell; determine a time domainstructure of the one or more subframes; and perform an initial access toa cell based on the one or more detected discovery signaling blocks, thedetermined beam and the time domain structure of the one or moresubframes.
 2. The apparatus according to claim 1, wherein one ormultiple of the discovery signaling blocks are included in a group. 3.The apparatus according to claim 2, wherein the discovery signalingblocks comprise group information comprising information on how manydiscovery signaling blocks are in the group.
 4. The apparatus accordingto claim 1, wherein the discovery signaling blocks comprise mappinginformation that indicates where a discovery signaling block is locatedin the subframe structure.
 5. The apparatus according to claim 1,wherein at least one of the discovery signaling blocks comprisestransmission of a plurality of signals from one or multiple radiofrequency beams, and the one or multiple radio frequency beams used forthe transmission of the signals in a given discovery signaling block arethe same.
 6. The apparatus according to claim 2, wherein the one ormultiple discovery signaling blocks of the group are locatedconsecutively in time or in a clustered manner in time.
 7. The apparatusaccording to claim 1, wherein each of the discovery signaling blocks isself-detectable or self-decodable.
 8. The apparatus according to claim2, wherein the discovery signaling blocks are mapped in a subframestarting from the end of the data symbols, when a size of the group isgreater than one.
 9. The apparatus according to claim 2, wherein thediscovery signaling blocks are mapped in a subframe on at least one of adownlink control symbol or downlink data symbol when a size of the groupis one.
 10. A method, comprising: detecting in a subframe structure oneor more discovery signaling blocks associated with indices, wherein adiscovery signaling block comprises at least a synchronization signaland a physical broadcast channel; based on the associated indices of theone or more detected discovery signaling blocks, determining a groupstructure of the discovery signaling blocks; based on the groupstructure of the discovery signaling blocks, determining a beam amongthe beams of the cell; determining a time domain structure of the one ormore subframes; and performing an initial access to a cell based on theone or more detected discovery signaling blocks, the determined beam andthe time domain structure of the one or more subframes.
 11. The methodaccording to claim 10, wherein one or multiple of the discoverysignaling blocks are included in a group.
 12. The method according toclaim 11, wherein the discovery signaling blocks comprise groupinformation comprising information on how many discovery signalingblocks are in the group.
 13. The method according to claim 10, whereinthe discovery signaling blocks comprise mapping information thatindicates where a discovery signaling block is located in the subframestructure.
 14. The method according to claim 10, wherein a discoverysignaling block comprises transmission of a plurality of signals fromone or multiple radio frequency beams, and the one or multiple radiofrequency beams used for the transmission of the signals in a givendiscovery signaling block are the same.
 15. The method according toclaim 11, wherein the one or multiple discovery signaling blocks of thegroup are located consecutively in time or in a clustered manner intime.
 16. The method according to claim 10, wherein each of thediscovery signaling blocks is self-detectable or self-decodable.
 17. Anapparatus, comprising: at least one processor; and at least one memorycomprising computer program code, the at least one memory and thecomputer program code are configured, with the at least one processor,to cause the apparatus at least to configure, in a subframe structure,one or more discovery signaling blocks associated with indices, whereina discovery signaling block comprises at least a synchronization signaland a physical broadcast channel; map the discovery signaling blocksonto a subframe structure; include group information into each of thediscovery signaling blocks; and transmit the discovery signaling blocksin the subframe structure.
 18. The apparatus according to claim 17,wherein, to include the group information, the at least one memory andthe computer program code are configured, with the at least oneprocessor, to cause the apparatus at least to include mappinginformation which indicates where a discovery signaling block is locatedin the subframe structure.
 19. The apparatus according to claim 17,wherein the group information comprises information on how manydiscovery signaling blocks are in a group of discovery signaling blocks.20. The apparatus according to claim 17, wherein at least one of thediscovery signaling blocks comprises transmission of a plurality ofsignals from one or multiple radio frequency beams, and the one ormultiple radio frequency beams used for the transmission of the signalsin a given discovery signaling block are the same.